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https://www.readbyqxmd.com/read/28239774/change-of-monascus-pigment-metabolism-and-secretion-in-different-extractive-fermentation-process
#1
Gong Chen, Rui Tang, Xiaofei Tian, Peng Qin, Zhenqiang Wu
Monascus pigments that were generally produced intracellularly from Monascus spp. are important natural colorants in food industry. In this study, change of pigment metabolism and secretion was investigated through fed-batch extractive fermentation and continuous extractive fermentation. The biomass, secreting rate of pigment and total pigment yield closely correlated with the activated time of extractive fermentation as well as the composition of feeding nutrients. Metal ions played a key role in both the cell growth and pigment metabolism...
February 26, 2017: Bioprocess and Biosystems Engineering
https://www.readbyqxmd.com/read/28239690/characterization-of-peptide-attachment-on-silicon-nanowires-by-x-ray-photoelectron-spectroscopy-and-mass-spectrometry
#2
Ievgen Kurylo, Mathieu Dupré, Sonia Cantel, Christine Enjalbal, Hervé Drobecq, Sabine Szunerits, Oleg Melnyk, Rabah Boukherroub, Yannick Coffinier
In this paper, we report an original method to immobilize a model peptide on silicon nanowires (SiNWs) via a photolinker attached to the SiNWs' surface. The silicon nanowires were fabricated by a metal assisted chemical etching (MACE) method. Then, direct characterization of the peptide immobilization on SiNWs was performed either by X-ray photoelectron spectroscopy (XPS) or by laser-desorption/ionization mass spectrometry (LDI-MS). XPS allowed us to follow the peptide immobilization and its photorelease by recording the variation of the signal intensities of the different elements present on the SiNW surface...
February 27, 2017: Analyst
https://www.readbyqxmd.com/read/28239205/a-study-of-the-dissociative-recombination-of-cao-with-electrons-implications-for-ca-chemistry-in-the-upper-atmosphere
#3
D L Bones, M Gerding, J Höffner, Juan Carlos Gómez Martín, J M C Plane
The dissociative recombination of CaO(+) ions with electrons has been studied in a flowing afterglow reactor. CaO(+) was generated by the pulsed laser ablation of a Ca target, followed by entrainment in an Ar(+) ion/electron plasma. A kinetic model describing the gas-phase chemistry and diffusion to the reactor walls was fitted to the experimental data, yielding a rate coefficient of (3.0 ± 1.0) × 10(-7) cm(3) molecule(-1) s(-1) at 295 K. This result has two atmospheric implications. First, the surprising observation that the Ca(+)/Fe(+) ratio is ~8 times larger than Ca/Fe between 90 and 100 km in the atmosphere can now be explained quantitatively by the known ion-molecule chemistry of these two metals...
December 28, 2016: Geophysical Research Letters
https://www.readbyqxmd.com/read/28239057/immobilization-of-lipase-from-geobacillus-sp-and-its-application-in-synthesis-of-methyl-salicylate
#4
Kamal Kumar Bhardwaj, Nitin Kumar Saun, Reena Gupta
The present study showed unique properties of an alkaline, thermophilic lipase of Geobacillus sp. which was isolated from soil of hot spring. The study was aimed to investigate the optimum immobilization conditions of lipase onto silica gel matrix (100-200 mesh) by surface adsorption method and its application in the synthesis of methyl salicylate. Lipase immobilized by surface adsorption onto silica pretreated with 4% glutaraldehyde showed 74.67% binding of protein and the optimum binding time for glutaraldehyde was found to be 2 h...
February 24, 2017: Journal of Oleo Science
https://www.readbyqxmd.com/read/28238440/the-proteolytic-system-of-pineapple-stems-revisited-purification-and-characterization-of-multiple-catalytically-active-forms
#5
André Matagne, Laetitia Bolle, Rachida El Mahyaoui, Danielle Baeyens-Volant, Mohamed Azarkan
Crude pineapple proteases extract (aka stem bromelain; EC 3.4.22.4) is an important proteolytic mixture that contains enzymes belonging to the cysteine proteases of the papain family. Numerous studies have been reported aiming at the fractionation and characterization of the many molecular species present in the extract, but more efforts are still required to obtain sufficient quantities of the various purified protease forms for detailed physicochemical, enzymatic and structural characterization. In this work, we describe an efficient strategy towards the purification of at least eight enzymatic forms...
February 23, 2017: Phytochemistry
https://www.readbyqxmd.com/read/28238435/lateral-and-longitudinal-patterns-of-water-physico-chemistry-and-trace-metal-distribution-and-partitioning-in-a-large-river-floodplain
#6
Dorothea Hug Peter, Emmanuel Castella, Vera I Slaveykova
Floodplain water bodies provide habitat to diversified ecological communities. Floodplains are also among the most impacted aquatic ecosystems. While the link between the lateral connectivity of floodplain sites to the main channel and their plant, fish and invertebrate communities has been well established, detailed information on chemical characteristics and particularly on trace metal spatial distribution and partitioning is scarce. The aim of this study was to examine the link between the lateral connectivity and physico-chemical variables, their trace metal concentrations and partitioning as well as the upstream-downstream gradient of these parameters...
February 23, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28238010/verification-of-implant-surface-modification-by-a-novel-processing-method
#7
Yoshiki Okada, Nobuhiro Abe, Noriyuki Hisamori, Toshiaki Kaneeda, Shigeaki Moriyama, Hitoshi Ohmori, Masayoshi Mizutani, Hiroyuki Yanai, Yoshio Nakashima, Yusuke Yokoyama, Toshifumi Ozaki
Metals have been used clinically as biomaterials, especially in the orthopaedic and dental fields. Metals used as implants wear at contact surfaces, producing metal particles and metal ions that may be harmful. Newly developed metal implants and methods of implant surface modification are currently under scrutiny. We evaluated the use of electrolytic in-process dressing (ELID) as a surface finishing method for metal implants. Metal implants processed using the ELID method (ELID group) or not processed (Non-ELID group) were inserted surgically into rabbit femurs...
February 2017: Acta Medica Okayama
https://www.readbyqxmd.com/read/28237756/the-retained-templates-as-helpers-for-the-spherical-meso-silica-in-adsorption-of-heavy-metals-and-impacts-of-solution-chemistry
#8
Zhijie Liang, Wenxin Shi, Zhiwei Zhao, Tianyi Sun, Fuyi Cui
The spherical mesoporous silica (meso-silica) MCM-41 and those with different dosage of the retained templates were prepared and characterized. Particularly, effects of the retained template and its dosage on the adsorption of typical heavy metals (Cu(2+) and Cd(2+)) in the synthesized materials were investigated. The results indicated that the retained templates acted as "helpers" for the adsorption of Cu(2+) and Cd(2+) in the spherical meso-silica MCM-41, and the maximum adsorption capacities (Qmax) increased with the increase of the retained template dosage...
February 12, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28237731/rhenium-i-tricarbonyl-compounds-of-bioactive-thiosemicarbazones-synthesis-characterization-and-activity-against-trypanosoma-cruzi
#9
Esteban Rodríguez Arce, Ignacio Machado, Belén Rodríguez, Michel Lapier, María Carolina Zúñiga, Juan Diego Maya, Claudio Olea Azar, Lucía Otero, Dinorah Gambino
American Trypanosomiasis is a chronic infection discovered and described in 1909 by the Brazilian scientist Carlos Chagas. It is caused by the protozoan parasite Trypanosoma cruzi. Although it affects about 10million people in Latin America, the current chemotherapy is still inadequate. The discovery of new drugs is urgently needed. Our group is focused on the development of prospective metal-based drugs mainly based on bioactive ligands and pharmacologically interesting metal ions. In this work three new rhenium(I) tricarbonyl compounds fac-[Re(I)(CO)3Br(HL)] where HL=5-nitrofuryl containing thiosemicarbazones were synthesized and fully characterized in solution and in the solid state...
January 23, 2017: Journal of Inorganic Biochemistry
https://www.readbyqxmd.com/read/28237674/endophytic-fungus-purpureocillium-sp-a5-protect-mangrove-plant-kandelia-candel-under-copper-stress
#10
Bin Gong, Guixiang Liu, Rquan Liao, Jingjing Song, Hong Zhang
Mangrove is an important ecosystem in the world. Mangrove ecosystems have a large capacity in retaining heavy metals, and now they are usually considered as sinks for heavy metals. However, the mechanism of why the soil of mangrove ecosystems can retain heavy metal is not certain. In this research, endophytic fungus Purpureocillium sp. A5 was isolated and identified from the roots of Kandelia candel. When this fungus was added, it protected the growth of K. candel under Cu stress. This can be illustrated by analyzing chlorophyll A and B, RWC and WSD to leaves of K...
February 9, 2017: Brazilian Journal of Microbiology: [publication of the Brazilian Society for Microbiology]
https://www.readbyqxmd.com/read/28237306/influence-of-phosphate-on-phytotoxicity-of-ceria-nanoparticles-in-an-agar-medium
#11
Guohua Wang, Yuhui Ma, Peng Zhang, Xiao He, Zhaohui Zhang, Meihua Qu, Yayun Ding, Junzhe Zhang, Changjian Xie, Wenhe Luo, Jing Zhang, Shengqi Chu, Zhifang Chai, Zhiyong Zhang
Fate and toxicity of manufactured nanoparticles (NPs) in the living organisms and the environment are highly related to their transformation. In the present study, the effect of phosphate on the phytotoxicity and transformation of CeO2 NPs was investigated in an agar medium using head lettuce plants that are sensitive to Ce(3+) ions. Plants were treated by CeO2 NPs with or without phosphate for 10 days. Results suggest that the treatments of P deficiency (P(-)) and CeO2 NPs (P(+)&Ce) could separately induce significant inhibition on the growth of lettuce seedlings and cause oxidative stress, but the inhibition was the most serious when the two conditions were combined (P(-)&Ce)...
February 22, 2017: Environmental Pollution
https://www.readbyqxmd.com/read/28236682/spectroscopic-and-theoretical-studies-of-charge-transfer-interaction-of-1-2-pyridylazo-2-napthol-with-nitroaromatics
#12
Animesh Karmakar, Bula Singh
1-(2-Pyridylazo)-2-napthol (hereafter 1Q) is widely used as a chelating ligand applied in chelatometric, spectrophotometric analysis of metal ions. It appeared from the literature survey that no inclusion complex of 1Q was reported with nitroaromatics. The formation of charge-transfer complex gives an opportunity to improve the physico-chemical properties of different donors. So the complex of 1Q with 4-nitrophenol (4-NP), 2,4-dinitrophenol (2,4-DNP), picric acid (PA), and 3,5-dinitrosalicylic acid (3,5-DNSA) was described in this work in methanol medium...
January 26, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28235456/detection-of-histidine-rich-glycoprotein-and-fibrinogen-with-nickel-enzyme-conjugates-purification-of-rabbit-hrg
#13
Mathia Colwell, Najma Ahmed, Ralph Butkowski
Nickel-bound alkaline phosphatase and peroxidase enzymes were used to investigate nickel binding to plasma proteins. Rabbit plasma dilutions to 25,000 were positive by ELISA, while Western blot analysis showed a prominent reaction with histidine-rich glycoprotein (HRG)(1) and lower reaction with fibrinogen (Fgn). To confirm their identities, purified HRG and Fgn were demonstrated to react with the nickel-bound enzymes by Western analysis. With disulfide bonds reduced, HRG and Fgn α-chain reactions were demonstrated...
February 21, 2017: Analytical Biochemistry
https://www.readbyqxmd.com/read/28235369/halloysite-nanotubes-supported-ag-and-zno-nanoparticles-with-synergistically-enhanced-antibacterial-activity
#14
Zhan Shu, Yi Zhang, Qian Yang, Huaming Yang
Novel antimicrobial nanocomposite incorporating halloysite nanotubes (HNTs) and silver (Ag) into zinc oxide (ZnO) nanoparticles is prepared by integrating HNTs and decorating Ag nanoparticles. ZnO nanoparticles (ZnO NPs) and Ag nanoparticles (Ag NPs) with a size of about 100 and 8 nm, respectively, are dispersively anchored onto HNTs. The synergistic effects of ZnO NPs, Ag NPs, and HNTs led to the superior antibacterial activity of the Ag-ZnO/HNTs antibacterial nanocomposites. HNTs facilitated the dispersion and stability of ZnO NPs and brought them in close contact with bacteria, while Ag NPs could promote the separation of photogenerated electron-hole pairs and enhanced the antibacterial activity of ZnO NPs...
December 2017: Nanoscale Research Letters
https://www.readbyqxmd.com/read/28231533/synthesis-characterization-and-dna-binding-cleavage-protein-binding-and-cytotoxicity-studies-of-co-ii-ni-ii-cu-ii-and-zn-ii-complexes-of-aminonaphthoquinone
#15
A Kosiha, C Parthiban, Kuppanagounder P Elango
The Co(II), Ni(II), Cu(II) and Zn(II) complexes of an aminonaphthoquinone ligand (L) have been prepared and characterized using analytical and spectral techniques. The structures of L and its Zn(II) complex are confirmed by single crystal X-ray diffraction study. The results indicate that Co(II), Ni(II) and Zn(II) complexes possess tetrahedral geometry while Cu(II) complex exhibits square planar structure. The interaction of L and its complexes with CT-DNA reveal that they could interact with CT-DNA through intercalation...
February 16, 2017: Journal of Photochemistry and Photobiology. B, Biology
https://www.readbyqxmd.com/read/28231453/siderophore-transport-by-mmpl5-mmps5-protein-complex-in-mycobacterium-tuberculosis
#16
Padmani Sandhu, Yusuf Akhter
Iron is an essential metal ion required for the various physiological activities of bacteria. The pathogenic bacteria remain dependent on the host cell for their iron requirements and evolved with specialized scavenging machinery in the form of iron chelating siderophores. Mycobacterium tuberculosis has two types of siderophore molecules, mycobactin and carboxymycobactin. These are synthesized inside bacterial cells and need to be transported outside by specialized membrane associated proteins. MmpL5-MmpS5 (mycobacterial membrane protein large5-mycobacterial membrane protein small5) complex has been linked to the export of non-ferrated siderophores to extracellular environment but the precise molecular mechanism involved was largely unknown...
February 14, 2017: Journal of Inorganic Biochemistry
https://www.readbyqxmd.com/read/28230971/multifaceted-gold-palladium-bimetallic-nanorods-and-their-geometric-compositional-and-catalytic-tunabilities
#17
Lichao Sun, Qingfeng Zhang, Guangfang Grace Li, Esteban Villarreal, Xiaoqi Fu, Hui Wang
Kinetically controlled, seed-mediated coreduction provides a robust and versatile synthetic approach to multimetallic nanoparticles with precisely controlled geometries and compositions. Here we demonstrate that single-crystalline cylindrical Au nanorods selectively transform into a series of structurally distinct Au@Au-Pd alloy core-shell bimetallic nanorods with exotic multifaceted geometries enclosed by specific types of facets upon seed-mediated Au-Pd coreduction under diffusion controlled conditions. By adjusting several key synthetic parameters, such as the Pd/Au precursor ratio, the reducing agent concentration, the capping surfactant concentration, and foreign metal ion additives, we have been able to simultaneously fine-tailor the atomic-level surface structures and fine-tune the compositional stoichiometries of the multifaceted Au-Pd bimetallic nanorods...
February 23, 2017: ACS Nano
https://www.readbyqxmd.com/read/28230350/cyclic-voltammetry-probe-approach-curves-with-alkali-amalgams-at-mercury-sphere-cap-scanning-electrochemical-microscopy-probes
#18
Zachary J Barton, Joaquín Rodríguez-López
We report a method of precisely positioning a Hg-based ultramicroelectrode (UME) for scanning electrochemical microscopy (SECM) investigations of any substrate. Hg-based probes are capable of performing amalgamation reactions with metal cations, which avoid unwanted side reactions and positive feedback mechanisms that can prove problematic for traditional probe positioning methods. However, prolonged collection of ions eventually leads to saturation of the amalgam accompanied by irreversible loss of Hg. In order to obtain negative feedback positioning control without risking damage to the SECM probe, we implement cyclic voltammetry probe approach surfaces (CV-PASs), consisting of CVs performed between incremental motor movements...
February 23, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28230209/direct-observation-of-the-dynamics-of-single-metal-ions-at-the-interface-with-solids-in-aqueous-solutions
#19
Maria Ricci, William Trewby, Clodomiro Cafolla, Kislon Voïtchovsky
The dynamics of ions adsorbed at the surface of immersed charged solids plays a central role in countless natural and industrial processes such as crystal growth, heterogeneous catalysis, electrochemistry, or biological function. Electrokinetic measurements typically distinguish between a so-called Stern layer of ions and water molecules directly adsorbed on to the solid's surface, and a diffuse layer of ions further away from the surface. Dynamics within the Stern layer remain poorly understood, largely owing to a lack of in-situ atomic-level insights...
February 23, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28230105/interface-confined-hydrogen-evolution-reaction-in-zero-valent-metal-nanoparticles-intercalated-molybdenum-disulfide
#20
Zhongxin Chen, Kai Leng, Xiaoxu Zhao, Souradip Malkhandi, Wei Tang, Bingbing Tian, Lei Dong, Lirong Zheng, Ming Lin, Boon Siang Yeo, Kian Ping Loh
Interface confined reactions, which can modulate the bonding of reactants with catalytic centres and influence the rate of the mass transport from bulk solution, have emerged as a viable strategy for achieving highly stable and selective catalysis. Here we demonstrate that 1T'-enriched lithiated molybdenum disulfide is a highly powerful reducing agent, which can be exploited for the in-situ reduction of metal ions within the inner planes of lithiated molybdenum disulfide to form a zero valent metal-intercalated molybdenum disulfide...
February 23, 2017: Nature Communications
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